Pressurized capping apparatus

ABSTRACT

Apparatus for pressurizing the headspace of a filled plastic bottle while applying a cap includes a sealing ring having a surface for engaging a support ring, or other surface of known dimension, of the plastic bottle, clamping apparatus for moving the sealing ring, a chuck for holding the cap in a position to engage a finish of the plastic bottle, a pressure chamber surrounding the chuck having a sealing surface for contacting the sealing ring, a source of pressure coupled to the pressure chamber for introducing a volume of gas or vapor at super-atmospheric pressure into the chamber, and a motor for rotating the chuck and cap within the pressure chamber while the chamber is subjected to the gas or vapor at super-atmospheric pressure to seal the gas or vapor within the headspace of the filled plastic bottle with the cap.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is related to and claims all available benefit of U.S. Provisional Application 61/261,972 filed Nov. 17, 2009.

BACKGROUND

The present disclosure is directed to apparatus for capping plastic bottles, and particularly to apparatus for capping hot-filled plastic bottles having a threaded finish suitable for receiving an internally threaded cap. The present disclosure is additionally directed to such apparatus that would be used to apply an internally threaded cap to a plastic bottle having a molded finish that included a support ring situated below the threaded portion of the finish.

In a conventional hot-fill process employing plastic bottles, a hot beverage product is introduced into a plastic bottle, typically filling most of the bottle. The fluid is heated during a pasteurization or sterilization process to remove bacteria or other contamination, either immediately prior to or after the product is introduced into the plastic bottle. The plastic bottle is then hermetically sealed with a cap while the product is still hot. Subsequent to capping, the temperature of the liquid is allowed to cool from a high of about 185° Fahrenheit, the typical hot-fill temperature, to about 40° Fahrenheit, the typical refrigeration temperature. The change in temperature, from hot to cold, decreases the internal pressure of the sealed bottle and can creates a sub-atmospheric pressure or partial vacuum within the bottle primarily as a result of the thermal contraction of the liquid in the bottle. If the bottle cannot structurally support the pressure difference between the external ambient pressure and the lower internal pressure within the bottle, the decrease in internal pressure can cause the geometry of the bottle to distort and/or deform.

Current bottles are generally engineered to collapse at specific locations with vacuum panels and/or flexible bases to compensate for the decrease in internal pressure. These vacuum-reactive mechanisms are very efficient to maintain a balanced pressure and keep the remaining structural geometry of the bottle from collapsing. Vacuum panels, however, are sometimes difficult to mold. Further, labeling of the bottle is difficult because bottles employing raised and/or recessed vacuum panels often possess reduced surface area suitable for receiving a label. The reduction of suitable surface area also restricts the ornamental design of the label, restricts the placement of the label, and often leads to unattractive wrinkling of the label. Thus, there is a desire to employ in a hot-fill process bottles that avoid the use of any vacuum-reactive surface features so that the labeling process and end product can be more satisfactory to both the bottler and the consuming public.

Bottles that avoid the use of any vacuum-reactive surface features can be employed in a hot-fill process by suitably pressurizing the headspace of the filled bottle prior to applying and sealing any closure or cap. By suitably pressurizing the headspace prior to applying and sealing any closure, the pressure within the bottle will remain sufficient to avoid any distortion or deformation of the bottle during and subsequent to the cooling of the bottle and its contents from the usual hot-fill temperature down to the usual refrigerated temperature. Thus, there is a need for suitable equipment for pressurizing the headspace of the filled bottle prior to applying any closure that requires only the minimum of change to the fill line currently employed in hot-fill operations. There is also a need for such equipment that can be used on a variety of styles of plastic bottles, and can run at or close to the current speed of the fill line currently employed in hot-fill operations.

SUMMARY

An apparatus meeting these needs can include a sealing ring having a first surface for engaging a surface of known dimension immediately below the cap-engaging portion of a plastic bottle. One particularly suitable surface is presented by the support ring that is typically present at the bottom of the finish and above the blow-molded portions of the bottle. The apparatus can also include a clamping mechanism for moving the sealing ring from a position spaced from the surface of known dimension to a position engaging the surface of known dimension. A chuck can also be provided for holding a cap in a position to engage a finish on the plastic bottle. A pressure chamber can surround the chuck and can have a sealing surface for contacting a second surface of the sealing ring. The sealing surface of the chuck can be in sliding contact with the second surface of the sealing ring. A source of pressure can be coupled to the pressure chamber for introducing a volume of gas or vapor at super-atmospheric pressure into the chamber, preferably only when the sealing surface of the pressure chamber is in contact with the sealing ring and the sealing ring is engaging the surface of known dimension. The engagement between the sealing ring first surface and the surface of known dimension needs only to be sufficient to permit the build-up of pressure within the chamber and head space of the plastic bottle to a desired level. Apparatus can also be provided to rotate the chuck within the pressure chamber while the chamber is subjected to the gas or vapor at super-atmospheric pressure to seal the gas or vapor within the headspace of the hot-filled plastic bottle with the cap at the elevated charging pressure.

One feature of this apparatus is the ability to select the super-atmospheric pressure to which a given bottle is charged. In some instances the charging pressure may be selected such that upon cooling to the refrigeration temperature, the pressure within the bottle is approximately the same as normal atmospheric pressure so that removal of the cap from the bottle will not result in a large release of gas. In other circumstances, it may be desirable to select the charge pressure such that upon cooling to ambient room temperature the pressure within the bottle is sufficiently above normal atmospheric pressure as to aid in internally supporting the bottle under top loading that might occur in normal shipping of stacks of the filled bottles. A typical post-cooling interior pressure for such hot-filled beverages is between about 2 and 5 psi, but higher or lower pressures can be employed as desired. This ability to select the charging pressure has the advantage of permitting the use of a given filling and capping line on bottles having a wide variety of sizes, shapes and volumes.

Another feature of this apparatus is the ability to use the same capping equipment on a wide variety of plastic bottles. In some instances, the apparatus may need to be modified by a substitution of a suitably sized cap-holding chuck to accommodate different sized finishes. Usually, plastic bottles are molded with one of only a few selected standard finish sizes. The support ring associated with each of the various standard finish sizes is also quite uniform as is the outer surface of the finish above the support ring and below the cap-engaging features of the bottle. A small portion of the bottle immediately below the support ring, which is not altered in dimension by the blow-molding process, may also constitute a surface of known dimension. The most popular finish sizes in use today include 28 mm and 38 mm, but other standard finish sizes that can be used with this apparatus extend from 18 mm up to 132 mm. These standard finish sizes are used on a wide variety of bottles having different heights and volumes. Thus, capping equipment of a given finish size can be used on a wide variety of bottles, thus giving the bottler significant flexibility to adapt a specific filing and capping line to handle a wide range of bottles having a common finish size. Changing from one bottle size to another bottle size can be advantageously accomplished without any modification of a given apparatus of this type so long as the finish size remains unchanged, and the finish includes a corresponding standard sized support ring at a lower edge of the finish.

Another feature of the present apparatus is the ability to charge the head space of the bottle with a gas or vapor selected to be compatible with the liquid within the bottle. The gas or vapor can also be selected to resist any substantial transmission of the head space gas across the barrier presented by the plastic bottle itself. Both compressed air and nitrogen are desirable for minimizing this bottle barrier transmission of the head space gas subsequent to the application of the cap. Nitrogen has the additional desirable feature of low reactivity with most beverages that are likely to be bottled in this manner. For carbonated beverages, CO₂ may be the gas of choice.

Other features of the present apparatus and the corresponding advantages of those features will become apparent from the following discussion of the preferred embodiments of the present bottle, exemplifying the best mode of practice, which is illustrated in the accompanying drawings. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the features. Moreover, in the figures, like referenced numerals designate corresponding parts throughout the different views.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of an apparatus for pressurizing the headspace of a filled bottle prior to or during the application of a cap.

FIG. 2 is a partial sectional detail of a portion of the apparatus shown in FIG. 1.

FIG. 3 a-3 d is a schematic illustration of the method employed by the present apparatus.

DESCRIPTION OF A PREFERRED EMBODIMENT

An apparatus 10 for pressurizing the headspace of a previously filled bottle 12 and applying any cap 14 to a finish portion 11 of the bottle is shown in FIG. 1. The apparatus 10 can include a first support 16 for the bottle 12. The first support 16 is illustrated to be a platform 18 contacting a base 20 of the bottle. The first support 16 need not have the physical appearance shown in FIG. 1, and can be formed by any element of a filling line that supports the bottle 12 relative to a cap applying apparatus 22. The first support 16 can, for example, take the form of a driven belt or other bottle transport mechanism that supplies a continuous series of such bottles 12 to a filling and capping machine that incorporates an apparatus 10.

The apparatus 10 can also include a ring 24 that can be divided into at least two parts 24 a and 24 b, the parts being movable toward and away from a surface of known dimension on the bottle 12. Each of the parts of ring 24 can include a first surface 26 on an inner portion of the ring 24, shown in FIG. 2, that confronts the surface of known dimension, for example, a support ring 28, which is an injection molded feature at the lower edge of the finish portion 11 of the bottle 12 that is not dimensionally altered during the blow-molding of lower portions of the bottle 12. The movement of the parts of ring 24 away from the support ring 28 can be sufficient to permit the removal and insertion of the bottle 12 by the first support 16. The movement of the parts of the ring 24 toward the support ring 28 can be sufficient to engage the first surface 26 onto the support ring 28 of the bottle 12. The first surface 26 of the parts of the ring 24 can include a more or less conformable element 30 that can include a groove 31 that can seal against the support ring 28 of the bottle 12 to assist in the development of the pressure desired to pressurize the headspace of a previously filled bottle 12 as herein described. The parts of the ring 24 can be coupled to a clamping apparatus 32 that causes the movement of the parts of the ring 24 to move away and toward the support ring 28. The clamping apparatus 32 can take the form of a pneumatic or hydraulic piston and cylinder mechanism, an electrically powered solenoid, a pair of followers engaged on a power driven two-way threaded screw, or other suitable mechanism. As indicated previously, another surface of known dimension that is not altered during the blow-molding of the bottle 12 can be substituted for the support ring 28.

Movement of the bottle 12 by a bottle transport mechanism, which can include a supply of a continuous series of such bottles 12, can include a mechanism 34 for transporting each bottle 12 vertically in relation to the ring 24. The vertical transport mechanism 34 can take the form of a pneumatic or hydraulic piston and cylinder mechanism, an electrically powered solenoid, one or more followers engaged on a track including a ramp or incline, or other suitable mechanism. The vertical transport mechanism 34 can be calibrated or controlled such that the position of the support ring 28, or other surface of known dimension on the bottle 12, is suitably positioned for the correct engagement by the various parts of ring 24 prior to a capping operation. Following the completion of a capping operation, the vertical transport mechanism 34 can return the bottle to a lowered pre-capped vertical position. It is to be understood that the vertical transport mechanism 34 can move the bottle 12 in relation to the ring 24, or can move the ring 24 and associated devices in relation to the bottle 12.

The apparatus 10 can also include a pressure chamber 36 shown in section in FIGS. 1 and 2 to be defined by a generally cylindrical wall 38 have a closed upper end 40 and having a surface 42 at a lower margin of the cylindrical wall 38 for contacting a surface 44 of the sealing ring 24. The pressure chamber 36 can have other conformations including, for example, a hemispherical wall forming both portions 38 and 40. Alternatively, the generally cylindrical wall 38 can be formed by a rectangular or square wall. The surface 42 can include a more or less conformable element 46 that can seal against the surface 42 of the sealing ring 24 to assist in the development of the pressure desired to pressurize the headspace of a previously filled bottle 12 as herein described. The surface 42 is shown to be a planar upper surface of the sealing ring 24 against which the conformable element 46 can abut and, if necessary, slide as the parts of the sealing ring move relative to the support ring 28 or other surface of known dimension. The surface 42 can have other conformations that would enhance the capability of the pressure chamber 36 to achieve the desired pressure needed to sufficiently pressurize the headspace of a previously filled bottle 12. For example, the surface can take the form of a tapered ring surface adjacent to an outer edge of the sealing ring 24, which under the mating contact between the pressure chamber 36 could enhance the radial inward contact pressure applied by the first surface 26 and the conformable element 30 of the ring 24 against the support ring 28, or other surface of known dimension, thereby enhancing the ability to achieve the desired pressure level within the pressure chamber.

The apparatus 10 can also include a chuck 48, shown in FIG. 1, forming a cap applying apparatus 22 for holding the cap 14 in a position to engage the top of the finish of the plastic bottle 12. The chuck 48 can be coupled to a stem 50 that extends through a sealed opening 52 in the closed upper end 40 of the pressure chamber 36. A motor 54 can be coupled to the stem 50 for rotating the chuck 48 and cap 14 to engage the interior threads of the cap 14 onto the finish of the bottle 12. A mechanism 56 can be coupled between the motor 54 and/or stem 50 and the pressure chamber 36 to cause sufficient vertical movement of the stem 50 and chuck 48 during application of the cap 14 to ensure an adequate seal is achieved between the cap 14 and the finish of the bottle 12. The motor 54 and/or the stem 50 can be coupled to a torque sensor [not shown] that can sense the completion of the application of the cap to the finish portion 11 of the bottle 12. A further mechanism 58 can be coupled between the pressure chamber 36 and the ring 24 and/or the clamping apparatus 32 to cause any desired movement between the pressure chamber 36 and the ring 24. The range of movement by the mechanism 58 can include a the vertical movement necessary to clamp the more or less conformable element 46 of the pressure chamber 36 against the surface 42 of the sealing ring 24 during a pressurization and capping operation. The range of movement by the mechanism 58 and/or mechanism 56 can also include that movement necessary to allow for the introduction of a cap 14 from a cap supply (not illustrated) into the chuck 48.

The development of the pressure desired to pressurize the headspace of a previously filled bottle 12 can be achieved by coupling the pressure chamber 36 to an external source (not shown) of a gas or vapor selected to be compatible with the liquid within the bottle 12. The external source, which is expected to be typically maintained at about 10 to 40 psi, can be coupled to the pressure chamber 36 by a suitable conduit 60, which can include a valve 62 permitting the supply of the gas or vapor to, the pressure chamber 36 only when the pressure chamber 36 is engaged against the surface 42 of the sealing ring 24. The valve 62 can be controlled, for example, by a proximity switch 64 sensing the relative position between the pressure chamber 36 and sealing ring 24, or by other machine timing mechanisms. A pressure sensor 66 can also be coupled to the pressure chamber 36 and/or conduit 60, to sense any inadequate pressure development within the pressure chamber during a capping operation. The pressure sensor 66 can be coupled, for example, to suitable alarm or report generating apparatus to ensure that any systemic problems can be identified and quickly addressed.

The operation of the apparatus 10 can best be seen in connection with FIGS. 3 a-3 d, in which merely the finish portion 11 of a bottle 12, including support ring 28 is illustrated, the remainder of the bottle being omitted for clarity. The operation is initiated by situating a cap 14 within the capping chuck 48, and positioning the capping chuck 48 at an uppermost position within the pressure chamber 36 as shown in FIG. 3 a. A bottle 12, which has previously been filled, particularly hot filled, is situated so that an upper portion of the finish 11 of the bottle 12 extends into the pressure chamber 36 and the support ring 28 is vertically aligned with the clamping ring 24. In the next step, shown in FIG. 3 b, the clamping ring 24 is closed against the support ring 28 while the conformable element 46 of the pressure chamber 36 is maintained in sliding contact with the surface 42 of the sealing ring 24. Alternatively, if the pressure chamber 36 is spaced above the clamping ring 24, the clamping ring 24 is closed against the support ring 28 and the pressure chamber 36 is lowered in relation to the clamping ring 24 until a sealing engagement is established between the conformable element 46 of the pressure chamber 36 and the surface 42 of the sealing ring 24. Following the sealing of the pressure chamber 36 and clamping ring 24, a volume of a selected gas or vapor at super-atmospheric pressure is then introduced into the chamber 36 through the conduit 60, the volume being sufficient to raise the pressure within the head space of the bottle 12 to a desired pressure. In the next step, shown in FIG. 3 c, the pressure within the pressure chamber 36 is maintained at the desired pressure level, and the capping chuck 48 is lowered and rotated within the chamber 36 by stem 50 until the cap 14 is secured onto the finish portion 11 of the bottle 12. In the next step, shown in FIG. 3 d, the pressure supplied through the conduit 60 is terminated and the capping chuck 44 is retracted to disengage from the cap 12, which is now secured onto the finish portion 11 of the bottle 12. The clamping ring 24 is disengaged from the support ring 28, and the capped, pressurized bottle 12 is moved to a cooling location to be brought down at least to room ambient temperature.

While these features have been disclosed in connection with the illustrated preferred embodiment, other embodiments of the invention will be apparent to those skilled in the art that come within the spirit of the invention as defined in the following claims. 

1. Apparatus for pressurizing the headspace of a filled plastic bottle while applying a cap comprising: a sealing ring having a first surface for engaging a surface of known dimension on the plastic bottle, and a second surface, clamping apparatus for moving the sealing ring from a position spaced from the surface of known dimension to a position engaging the surface of known dimension, a chuck for holding a cap in a position to engage a finish of the plastic bottle, a pressure chamber surrounding the chuck having a sealing surface for contacting the sealing ring second surface, a source of pressure coupled to the pressure chamber for introducing a volume of gas or vapor at super-atmospheric pressure into the chamber, and apparatus for moving the chuck and cap within the pressure chamber while the chamber is subjected to the gas or vapor at super-atmospheric pressure to seal the gas or vapor within the headspace of the filled plastic bottle with the cap.
 2. The apparatus of claim 1, wherein the sealing ring first surface comprising a concave radial inner surface for engaging a radial outer surface of a support ring on the plastic bottle.
 3. The apparatus of claim 1, wherein the sealing ring second surface is an upwardly facing planar surface and the pressure chamber sealing surface is a downwardly facing surface including a circumferential seal for contacting the sealing ring second surface.
 4. The apparatus of claim 1, wherein the apparatus for moving the chuck and cap comprises a motor coupled to the chuck for rotating the chuck and cap and apparatus for moving the chuck and cap vertically within the pressure chamber.
 5. The apparatus of claim 1, wherein the source of pressurized gas or vapor comprises a source of pressurized air, nitrogen or CO₂.
 6. The apparatus of claim 1, further comprising apparatus for longitudinally moving the pressure chamber and clamping ring toward and away from each other.
 7. The apparatus of claim 6, further comprising a source of caps for supplying the chuck, and wherein the apparatus for longitudinally moving the pressure chamber and clamping ring includes a range of movement sufficient to permit a cap from the source of caps to be inserted into the chuck.
 8. The apparatus of claim 1, further comprising apparatus for moving the clamping ring and bottle relative to each other at least when the clamping ring is in the position spaced from the support ring.
 9. The apparatus of claim 4, wherein the pressure chamber comprises a peripheral wall including the sealing surface on a lower perimeter thereof, and an upper end wall closing the peripheral wall.
 10. The apparatus of claim 9, further comprising a central opening in the upper end wall including a seal surrounding a stem extending through the central opening and coupling the chuck to the motor.
 11. A method for applying a cap to a finish of a filled plastic bottle comprising: clamping a ring to a surface of known dimension on the bottle, positioning a chamber containing a chuck holding a cap over the finish of the bottle so that a lower edge of the chamber seals against the clamped ring, pressurizing the chamber and bottle interior with a volume of gas or vapor at a super atmospheric pressure, moving the chuck and cap within the chamber relative to the finish of the bottle to seal the gas or vapor within the bottle at the super atmospheric pressure, releasing the pressure within the pressure chamber, and unclamping the ring from the surface of known dimension.
 12. The method of claim 11, wherein the clamping step comprises engaging a radial outer surface of a support ring on the bottle with a sealing ring having a concave radial inner surface.
 13. The method of claim 11, wherein the positioning step comprises vertically moving one of the clamping ring and chamber in relation to the other.
 14. The method of claim 11, wherein the moving step comprises rotating the chuck and cap while moving the chuck and cap downward relative to the chamber.
 15. The method of claim 11, wherein the unclamping step is preceded by releasing the cap from the chuck.
 16. The method of claim 11, wherein the unclamping step is followed by moving at least one of the clamping ring and bottle relative to each other by a distance sufficient to position the clamping ring around a second bottle.
 17. The method of claim 16, further comprising the step of supplying a second cap to the chuck to be applied to the second bottle.
 18. A system for pressure capping bottles comprising: apparatus for supplying a series of bottles filled with a liquid to a desired fill point, each of the bottles having a finish suitable to engage a cap and a surface situated below the finish of uniform known dimension, a sealing ring having a first surface for engaging the surface of known dimension on the bottle, and a second surface, and clamping apparatus for moving the sealing ring from a position spaced from the series of bottles to a position engaging the surface of known dimension on a first of the series of bottles, a source of caps for supplying a chuck with a series of caps, the chuck being adapted to hold a cap in a position to engage a finish of one of the bottles, and a pressure chamber surrounding the chuck having a sealing surface for contacting the sealing ring second surface, a source of pressure coupled to the pressure chamber for introducing a sufficient volume of gas or vapor at super-atmospheric pressure into the chamber to pressurize the headspace within the bottle above the fill point to a desired pressure, and apparatus for moving the chuck and cap within the pressure chamber while the chamber is subjected to the gas or vapor at super-atmospheric pressure to seal the gas or vapor within the headspace of the bottle with the cap.
 19. The system of claim 18, wherein the pressure chamber comprises a peripheral wall including the sealing surface on a lower perimeter thereof for sealing engagement with an upper surface of the sealing ring, an upper end wall closing the peripheral wall, a central opening in the upper end wall including a seal surrounding a stem coupled to the chuck and extending through the central opening, and a motor for rotating the chuck relative to the pressure chamber.
 20. The system of claim 18, further comprising apparatus for vertically reciprocally moving the chuck and sealing ring in relation to the apparatus for supplying the series of bottles so that each bottle in the series is capped while containing a sufficient volume of gas or vapor at super-atmospheric pressure in the headspace within the bottle to a desired pressure. 